Two factors suggest the need for HIV prevention efforts focused on partnered young men who have sex with men (YMSM). First, HIV rates are rising in this population, which already bear a disproportionate burden of HIV infection. Second, main partnerships - rather than casual partners - account for a majority of new infections, and younger age has been associated with an increased risk of main partner transmission. Substance use remains a critical factor associated with HIV sexual transmission risk behavior. Couples based approaches to HIV testing have been developed for gay men and endorsed by the WHO and CDC; however, existing protocols do not include a focus on substance use. In addition, existing protocols are predicated on the assumption that members of the couple possess adequate assertive communication skills to discuss relationship agreements, which may be underutilized by YMSM. The proposed project will develop a novel intervention to reduce substance use and sexual risk behavior among partnered YMSM through the modification of an existing Couples Voluntary Counseling and Testing (CVCT) protocol originally created by Drs. Sullivan and Stephenson (co-investigators). The new intervention protocol will be informed by qualitative data gathered from 30 HIV testing providers and existing qualitative data from 21 gay couples. The new intervention will incorporate brief video segments modeling communication skills. The final two years of the project are devoted to a randomized clinical trial (RCT) comparing the new intervention to the standard CVCT protocol in a sample of 120 substance using YMSM and their partners. The RCT will utilize a Solomon 4 group design in order to examine the effects of pre- intervention assessment on substance use and sexual risk outcomes assessed at 3 and 6 month follow up. The study team is led by Dr. Tyrel J. Starks (PI), a new investigator with substantial experience in the analysis of dyadic data, who has collaborated on numerous projects examining the nature of sexual agreements and their association with substance use and HIV transmission risk behavior. He is supported by a team of seasoned investigators which includes Drs. Sullivan and Stephenson as well as Dr. Jeffrey Parsons. The team brings extensive experience in HIV prevention research generally and intervention development specifically.